Oxygen therapy is used to treat patients suffering from a wide variety of ailments and to assist in numerous treatments. One of the most important aspects of such therapy is obtaining the correct oxygen mixture and pressure of the treatment gas. A common form of oxygen therapy is accomplished through the use of a Continuous Positive Airway Pressure (CPAP) device. As those skilled in oxygen therapy will recognize, numerous other auxiliary therapy devices that require mixed gas are used in conjunction with CPAP therapy. Such auxiliary devices include nebulizers and resuscitation bags.
Medical compressed air and oxygen are mixed, or blended, to obtain the correct oxygen mixture and pressure of the treatment, or mixed, gas. While many oxygen therapy devices have the ability to properly mix the medical compressed air and oxygen built into the device, several devices do not, and require connection to an external gas blender so that the device is supplied with pre-mixed gas. The devices that incorporate the gas mixing capability include a gas blender. A gas blender is a device that properly mixes the medical compressed air and the oxygen to obtain a mixed gas with a specific oxygen percentage and pressure. It is desirable to have an integral gas blender that includes an auxiliary mixed gas outlet that can be used to supply mixed gas to equipment that does not have a built-in blender. Incorporation of such an auxiliary mixed gas outlet eliminates the need for an external gas blender for many pieces of equipment.
Presently a limited number of commercially available devices incorporate an auxiliary mixed gas outlet, but these devices have a number of drawbacks. First, it is believed that the presently available gas blenders having an auxiliary gas outlet can only supply mixed air via a treatment outlet or the auxiliary outlet, not both outlets at the same time. Secondly, presently available auxiliary gas outlets often can only supply mixed gas at low flow rates, thereby limiting the types of auxiliary equipment that can be supplied with the mixed gas from the auxiliary gas outlet.
The art needs a gas blender that can supply mixed air to a treatment outlet and an auxiliary gas outlet at the same time. Further, a gas blender that automatically adjusts during use of the auxiliary gas outlet so as not to affect the mixed gas flow from the treatment outlet is desirable. Additionally, an ideal gas blender will not unduly restrict the flow out of the auxiliary gas outlet.